It has been known for fishing near the bottom of a lake to employ a downrigger system wherein a relatively strong trolling line is played out from a rear of the boat and having a heavy weight attached thereto so that it descends substantially vertically to the bottom even during trolling motion. A fishing line is releasably attached to the weight so that when a fish strikes, the fishing line is released from the weight and the fisherman can play the fish without interference from the downrigger weight.
With such systems it is difficult to maintain the end of the trolling line with the weight near the bottom of the lake since the depth changes as the boat trolls.
To be effective, the fishing lure should follow the contour of the bottom since the fish hold around structure formations on the bottom.